Method for apparatus for determining measurement parameter of a fibrous object and whether the object is a valid object

ABSTRACT

Disclosed is a method/apparatus to determine any one of a plurality of parameters: shape, area, chemical composition, diameter, color, number, thickness, width, length, absorptivity, reflectivity, transmittivity, dielectric constant, raman scattering profile, fluorescence, surface tension, roughness, profile, density, position and orientation. Also use of a plurality of energy beams as source energy: charged and neutral particle beams, gamma-, X-, micro-, optical and acoustic waves. The described apparatus determines the mean and standard deviation of a plurality of diameters of wool fibers, and includes a He-Ne laser (101), and a pinhole (102) which produce an expanding laser beam which passes through cell (105). Beam splitter (103) is operatively disposed to pinhole (102) and laser (101) to direct a portion of the laser beam to reference detector (109) which is electrically connected to processor (110) via line (111). When apparatus (100) is operating wool fibers in an isopropanol-wool slurry pass through cell (105) generally at a non-zero degree angle to the direction of slurry flow through cell (105) to interact with the laser beam in cell (105 ). Beam splitter (104) and microscope objective (106) are operatively disposed with respect to laser (101), pinhole (102) and cell (105) to produce an in focus magnified transmission image of wool fibers in cell (105) in the plane of end (107) of optical fiber bundle (108). Each of the fibers in bundle (108) is connected to a photodiode detector (112). Processor/timer (113) is connected electrically to detector (112) by line (114). Processor/timer (113) is also connected electrically to computer (115) by line (116) and to processor (110) by line (117). Detector (118) is connected electrically to processor (110) by line (119). Processor (110) is connected electrically to computer (115) by line (120). Detector (118) is operatively disposed with respect to laser (101), pinhole (102) and cell (105) to detect outgoing light.

This invention relates to methods and apparatus for determining ameasurement parameter(s) of an object and whether the object is a validobject, for determining a first parameter(s) of a valid object, fordetermining a measurement parameter(s) of a valid object, fordetermining a measurement parameter(s) of an invalid object, fordetermining a first parameter(s) of an object and determining a firstparameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a first parameter(s) of avalid object, for determining a measurement parameter(s) and a firstparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a first parameter(s) ofan invalid object, for determining a first parameter(s) of a validobject and determining a measurement parameter(s) of an invalid object,and for determining a first parameter(s) of a valid object anddetermining a first parameter(s) of an invalid object.

BACKGROUND ART

A number of methods and apparatus have been developed for obtaining ameasurement of mean fibre diameter and fibre diameter distribution in asample containing; a plurality of wool fibres having differentdiameters.

Two classes of instruments for the measurement of mean fibre diameterare:

1. Those which give an estimate of average diameter only.

2. Those which also give the distribution of fibre diameters within asample including statistical information such as the variance of thediameters of the sample fibres.

In recent times the information given by the distribution of wool fibrediameter has come to be accepted as being required in somecircumstances.

To accurately estimate the distribution of the fibre diameters a largenumber of measurements have to be made.

A particular method for measuring mean fibre diameter and fibre diameterdistribution involves the measurements of fibre diameters in an opticalmicroscope using a calibrated graticule to gauge the fibre diameters.This method is slow, tedious and prone to errors. These errors can arisefrom a number of sources including the optics, the conditioning of thefibres, and the judgment of the operators. Measurement of a few thousandfibres using this technique takes many hours to complete.

An instrument for determining fibre diameter distribution has beenproposed by Lynch and Michie, Australian Patent No. 472,862 entitled"Optical Shadowing Method and Apparatus for Fibre Diameter Measurement".

In the apparatus described in 472,862 a light beam traverses atransparent measurement cell and falls on a photoelectric sensor.

Fibres dispersed and suspended in a clear liquid are caused to flowthrough the measurement cell and intercept the light beam. The reductionin the detected light intensity as a result of a fibre properlyoccluding the light beam is a function of the diameter of the fibre.

The apparatus includes a split photodetector and a processor to rejectreadings when a fibre end falls within the light beam. Ensuring that theamplitude of the signal from the two detecting elements of the splitphotodetector differed by less than 10%, was thought to be sufficientfor acceptance of the measurement.

Instruments manufactured according to the teaching of the Lynch andMichie patent have been available for many years and are used to measurethe diameter distribution of wool and other fibres.

Over this period a number of deficiencies, some of which are related tothe validity of the individual fibre measurements, have become apparent.

Firstly, equal light occlusion on the two halves of the split detectoris not sufficient to guarantee the validity or otherwise of ameasurement. For example it has been observed that the diameter of somefibres varies more than 30% in less length than the beam diameter. Thesefibres can give an unequal response from the two halves of the splitdetector circuitry which would in turn reject the measurement, eventhough the measurement should have been accepted. Alternatively,measurements of fibres that have not fully crossed the light beam havebeen observed to have been accepted when they should have been rejected.

Secondly, the Lynch and Michie proposal assumed that the fibre snippetswould be so dilute in the carrier liquid that the probability of twofibres being in the light beam at the same time would be negligible.

In practice, it has been found that for a typical measurement rate of100 fibres per second the proportion of occurrence where two fibresappear in the light beam at the same time is significant. This effectappears in the diameter distribution graph as a second hump at doublethe value of the real distribution hump. The second hump has asignificant affect on the second moment statistic, the variance.

The Lynch and Michie patent did not teach a method for rejecting thesignals representing the occurrence of two fibres measuredsimultaneously in the light beam, but practical realisation of theinstrument has included an apparatus whereby signal responses with adouble peak were interpreted as representing two fibres in the beamsimultaneously and were therefore rejected.

Observations have shown that the double peak detector does not pick upall multiple fibre events.

OBJECTS OF INVENTION

Objects of this invention are to provide methods and apparatus fordetermining a measurement parameter(s) of an object and whether theobject is a valid object, for determining a first parameter(s) of avalid object, for determining a measurement parameter(s) of a validobject, for determining a measurement parameter(s) of an invalid object,for determining a first parameter(s) of an object and determining afirst parameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a first parameter(s) of avalid object, for determining a measurement parameter(s) and a firstparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, for determining a measurementparameter(s) of a valid object and determining a first parameter(s) ofan invalid object, for determining a first parameter(s) of a validobject and determining a measurement parameter(s) of an invalid object,and for determining a first parameter(s) of a valid object anddetermining a first parameter(s) of an invalid object.

DISCLOSURE OF THE INVENTION

According to a first embodiment of this invention there is provided amethod for determining a measurement parameter(s) of an object andwhether the object is a valid object, comprising:

(a) passing a validating energy beam(s) through a validating interactionvolume(s);

(b) detecting validating outgoing energy originating from the validatingenergy beam(s) in the validating interaction volume(s), the detectionbeing in at least one validating focal plane of the validating outgoingenergy with respect to the validating interaction volume(s) anddetermining a validating parameter(s) from the detected validatingoutgoing energy;

(c) determining from the validating parameter(s) whether the validatingoutgoing energy originated from an interaction between an object and thevalidating beam(s) in the validating volume(s) and, on determining anobject;

(d) locating the object in a measurement interaction volume(s);

(e) passing a measurement energy beam(s) through the measurementinteraction volume(s) to interact with the object so as to producemeasurement outgoing energy;

(f) detecting at least a portion of the measurement outgoing energy inat least one measurement focal plane of the measurement outgoing energywith respect to the measurement interaction volume(s), the measurementfocal plane being different from the validating focal plane, anddetermining a measurement parameter(s) from the detected measurementoutgoing energy; and

(g) determining from the validating parameter(s) whether the object is avalid object.

According to a second embodiment of this invention there is provided amethod for determining a first parameter(s) of a valid object,comprising:

the method of the first embodiment; and, on determining a valid object,

(i') determining the first parameter(s) of the valid object from themeasurement parameter(s); and

(j') determining the first parameter(s) of the valid object as anacceptable valid object parameter(s).

According to a third embodiment of this invention there is provided amethod for determining a measurement parameter(s) of a valid object,comprising:

the method of the first embodiment; and, on determining a valid object,

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s).

According to a fourth embodiment of this invention there is provided amethod for determining a measurement parameter(s) of an invalid object,comprising:

the method of the first embodiment; and, on determining an invalidobject,

(h") determining the measurement parameter(s) of the invalid object asan unacceptable valid object parameter(s).

According to a fifth embodiment of this invention there is provided amethod for determining a first parameter(s) of an object and determininga first parameter(s) of an invalid object, comprising:

steps (a) to (g) of the first embodiment;

(i) determining the first parameter(s) of the object from themeasurement parameter(s); and, on determining an invalid object,

(j") determining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s).

According to a sixth embodiment of this invention there is provided amethod for determining a measurement parameter(s) of a valid object anddetermining a measurement parameter(s) of an invalid object, comprising:

steps (a) to (g) of the first embodiment; and,

(I) on determining a valid object,

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s);

(II) on determining an invalid object,

(h") determining the measurement parameter(s) of the invalid object asan unacceptable valid object parameter(s).

According to a seventh embodiment of this invention there is provided amethod for determining a measurement parameter(s) of a valid object anddetermining a first parameter(s) of a valid object, comprising:

steps (a) to (g) of the first embodiment; and,

on determining a valid object,

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s);

(i') determining the first parameter(s) of the object from themeasurement parameter(s);

(j') determining the first parameter(s) of the valid object asacceptable valid object parameter(s).

According to a eighth embodiment of this invention there is provided amethod for determining a measurement parameter(s) and a firstparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, comprising:

steps (a) to (g) of the first embodiment; and,

(I) on determining a valid object,

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s);

(i') determining the first parameter(s) of the object from themeasurement parameter(s);

(j') determining the first parameter(s) of the valid object as anacceptable valid object parameter(s);

(II) on determining an invalid object,

(h") determining the measurement parameter(s) of the invalid object asan unacceptable valid object parameter(s).

According to a ninth embodiment of this invention there is provided amethod for determining a measurement parameter(s) of a valid object anddetermining a first parameter(s) of an invalid object, comprising:

steps (a) to (g) of the first embodiment; and,

(I) on determining a valid object,

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s);

(II) on determining an invalid object,

(i") determining the first parameter(s) of the object from themeasurement parameter(s);

(j") determining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s).

According to a tenth embodiment of this invention there is provided amethod for determining a first parameter(s) of a valid object anddetermining a measurement parameter(s) of an invalid object, comprising:

steps(a) to(g) of the first embodiment; and,

(I) on determining a valid object.

(i') determining the first parameter(s) of the object from themeasurement parameter(s);

(j') determining the first parameter(s) of the valid object as anacceptable valid object parameter(s).

(II) on determining an invalid object,

(h") determining the measurement parameter(s) of the invalid object asan unacceptable valid object parameter(s).

According to an eleventh embodiment of this invention there is provideda method for determining a first parameter(s) of a valid object anddetermining a first parameter(s) of an invalid object, comprising:

steps(a) to (g) of the first embodiment; and,

(i) determining the first parameter(s) of the object from themeasurement parameter(s);

(I) on determining a valid object,

(j') determining the first parameter(s) of the valid object as anacceptable valid object parameter(s).

(II) on determining an invalid object,

(j") determining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s).

Generally, the method of the first embodiment further includes at leastone of the following steps in an appropriate workable sequence:

(i) determining the first parameter(s) of the object from themeasurement parameter(s);

(k) storing the measurement parameter(s) of the object;

(l) storing the first parameter(s) of the object;

(m) retrieving the measurement parameter(s) of the object;

(n) retrieving the first parameter(s) of the object;

(o) storing the validating parameter(s) of the object;

(p) retrieving the validating parameter(s) of the object;

(q) storing the object validation;

(r) retrieving the object validation;

(h') determining the measurement parameter(s) of the valid object as anacceptable valid object parameter(s).

(i') determining the first parameter(s) of the valid object from themeasurement parameter(s);

(j') determining the first parameter(s) of the valid object as anacceptable valid object parameter(s);

(k') storing the measurement parameter(s) of the valid object;

(l') storing the first parameter(s) of the valid object;

(m') retrieving the measurement parameter(s) of the valid object;

(n') retrieving the first parameter(s) of the valid object;

(h") determining the measurement parameter(s) of the invalid object asan unacceptable valid object parameter(s).

(i") determining the first parameter(s) of the invalid object from themeasurement parameter(s);

(j") determining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s);

(k") storing the measurement parameter(s) of the invalid object;

(l") storing the first parameter(s) of the invalid object;

(m") retrieving the measurement parameter(s) of the invalid object;

(n") retrieving the first parameter(s) of the invalid object.

Generally, the validating energy beam(s) is the same as the measurementenergy beam(s) and is an expanding beam of light emerging from a pinholeilluminated by a collimated light beam or is a collimated light beam;

the validation interaction volume(s) is the same as the measurementinteraction volume(s) and is one interaction volume;

the validating parameter(s) is the intensity from at least part of animage of the interaction volume produced using the validating outgoingenergy, the validating outgoing energy being in the form of light; and

the measurement parameter(s) is the intensity of at least a portion ofthe measurement outgoing energy said measurement outgoing energy being adiffraction pattern produced by light not occluded by the object.

Typically the light beam is a laser light beam.

The methods may include the step of focussing outgoing energyoriginating from the energy beams in the interaction volumes to provideat least one image of at least a portion(s) of the interaction volumesin the focal plane(s) which image(s) may be a virtual image(s) or a realimage(s), in focus or out of focus.

In the first to eleventh embodiments the validating and measurementinteraction volume(s) may be the same interaction volume(s), includeportions of the same interaction volume(s), or be different interactionvolume(s).

If the validating interaction volume(s) is the same as the measurementinteraction volume(s) then the step of determining that an object thatinteracted with the validating energy beam(s) in the validatinginteraction volume(s) to give rise to the validating outgoing energyfrom which the validating parameter(s) was detected is in a measurementinteraction volume(s), may be the same as determining from thevalidating parameter(s) whether the validating outgoing energyoriginated from an interaction between a valid object and the validatingbeam(s) in the validating volume(s).

In the first to eleventh embodiments the validating and measurementenergy beam(s) may be the same energy beam(s), include portions of thesame energy beam(s), or be different energy beam(s).

Each of the methods of the first to eleventh embodiments may be repeateda plurality of times and may include:

determining statistical information in respect of a plurality of themeasurement parameter(s) and/or the first and/or the validatingparameter(s) and/or object validation.

The methods of the first to eleventh embodiments may further comprise:

outputting and/or discarding invalid and/or valid first parameter(s)and/or validating parameter(s) and/or measurement parameter(s) and/orthe determination from the validating parameter(s) whether thevalidating outgoing energy originated from an interaction between avalid object and the validating beam(s) in the validating volume(s).

The method of the first to eleventh embodiments may include:

passing an object through the validating and measurement volume(s).

Generally, the validating energy beam(s) is the same as the measurementenergy beam(s) and is an expanding beam of light emerging from a pinholeilluminated by a collimated light beam or is a collimated light beam;

the validation interaction volume(s) is the same as the measurementinteraction volume(s) and is one interaction volume;

the validating parameter(s) is the intensity from at least part of animage of the interaction volume produced using the validating outgoingenergy, the validating outgoing energy being in the form of light;

the measurement parameter(s) is the intensity of at least a portion ofthe measurement outgoing energy said measurement outgoing energy being adiffraction pattern;

a valid object comprises a fibre selected from the group consisting of asheep wool fibre and goat hair; and

has a preselected length in a preselected position and orientation inthe validation and measurement interaction volume(s) and the firstparameter(s) is the diameter of the fibre.

According to a twelfth embodiment of this invention there is provided anapparatus for determining a measurement parameter(s) of an object andwhether the object is a valid object, comprising:

(a) a validating energy source(s) for passing a validating energybeam(s) through a validating interaction volume(s);

(b) a validating detector(s) for detecting validating outgoing energyoriginating from the validating energy beam(s) in the validatinginteraction volume(s), the detection being in at least one validatingfocal plane of the validating outgoing energy with respect to thevalidating interaction volume(s) and means for determining a validatingparameter(s) from the detected validating outgoing energy operativelyassociated with the validating detector(s), the validating detector(s)being operatively associated with the validating energy source(s);

(c) verification means for determining from the validating parameter(s)whether the validating outgoing energy originated from an interactionbetween an object and the validating beam(s) in the validating volume(s)the verification means being operatively associated with the validatingdetector(s);

(d) means for locating the object of (c) in a measurement interactionvolume(s) the means for locating being operatively associated with theverification means;

(e) a measurement energy source(s) for passing a measurement energybeam(s) through the measurement interaction volume(s) to interact withthe object so as to produce measurement outgoing energy;

(f) a measurement detector(s) for detecting at least a portion of themeasurement outgoing energy in at least one measurement focal plane ofthe measurement outgoing energy with respect to the measurementinteraction volume(s), the measurement focal plane being different fromthe validating focal plane, and means for determining a measurementparameter(s) from the detected measurement outgoing energy operativelyassociated with the measurement detector(s), the measurement detector(s)being operatively associated with the measurement energy source(s); and

(g) means for determining from the validating parameter(s) whether theobject is a valid object, the means for determining being operativelyassociated with the validating detector(s).

According to a thirteenth embodiment of this invention there is providedan apparatus for determining a validating parameter(s) and a firstparameter(s) of an object, comprising:

the apparatus of the twelfth embodiment; and,

means for determining the first parameter(s) of the object from themeasurement parameter(s), operatively associated with the measurementdetector(s).

According to a fourteenth embodiment of this invention there is providedan apparatus for determining a first parameter(s) of a valid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the first parameter(s) of the valid object fromthe measurement parameter(s) and for determining the first parameter(s)of the valid object as an acceptable valid object parameter(s),operatively associated with the measurement detector(s) and the meansfor determining from the validating parameter(s) whether the object is avalid object.

According to a fifteenth embodiment of this invention there is providedan apparatus for determining a measurement parameter(s) of a validobject, comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the valid objectas an acceptable valid object parameter(s), operatively associated withthe measurement detector(s) and the means for determining from thevalidating parameter(s) whether the object is a valid object.

According to a sixteenth embodiment of this invention there is providedan apparatus for determining a measurement parameter(s) of an invalidobject, comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the invalid objectas an unacceptable valid object parameter(s), operatively associatedwith the measurement detector(s) and the means for determining from thevalidating parameter(s) whether the object is a valid object.

According to a seventeenth embodiment of this invention there isprovided an apparatus for determining a first parameter(s) of an objectand determining a first parameter(s) of an invalid object, comprising:

the apparatus of the twelfth embodiment;

means for determining the first parameter(s) of the object from themeasurement parameter(s) and for determining the first parameter(s) ofthe invalid object as an unacceptable valid object parameter(s),operatively associated with the measurement detector(s) and the meansfor determining from the validating parameter(s) whether the object is avalid object.

According to a eighteenth embodiment of this invention there is providedan apparatus for determining a measurement parameter(s) of a validobject and determining a measurement parameter(s) of an invalid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the valid objectas an acceptable valid object parameter(s) and for determining themeasurement parameter(s) of the invalid object as an unacceptable validobject parameter(s), operatively associated with the measurementdetector(s) and the means for determining from the validatingparameter(s) whether the object is a valid object.

According to a nineteenth embodiment of this invention there is providedan apparatus for determining a measurement parameter(s) of a validobject and determining a first parameter(s) of a valid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the valid objectas an acceptable valid object parameter(s) and for determining the firstparameter(s) of the object from the measurement parameter(s) and fordetermining the first parameter(s) of the valid object as acceptablevalid object parameter(s), operatively associated with the measurementdetector(s) and the means for determining from the validatingparameter(s) whether the object is a valid object.

According to a twentieth embodiment of this invention there is providedan apparatus for determining a measurement parameter(s) and a firstparameter(s) of a valid object and determining a measurementparameter(s) of an invalid object, comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the valid objectas an acceptable valid object parameter(s) and for determining the firstparameter(s) of the object from the measurement parameter(s) and fordetermining the first parameter(s) of the valid object as an acceptablevalid object parameter(s) and for determining the measurementparameter(s) of the invalid object as an unacceptable valid objectparameter(s), operatively associated with the measurement detector(s)and the means for determining from the validating parameter(s) whetherthe object is a valid object.

According to a twenty first embodiment of this invention there isprovided an apparatus for determining a measurement parameter(s) of avalid object and determining a first parameter(s) of an invalid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the measurement parameter(s) of the valid objectas an acceptable valid object parameter(s) and for determining the firstparameter(s) of the object from the measurement parameter(s) and fordetermining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s), operatively associated with themeasurement detector(s) and the means for determining from thevalidating parameter(s) whether the object is a valid object.

According to a twenty second embodiment of this invention there isprovided an apparatus for determining a first parameter(s) of a validobject and determining a measurement parameter(s) of an invalid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the first parameter(s) of the object from themeasurement parameter(s) and for determining the first parameter(s) ofthe valid object as an acceptable valid object parameter(s) and fordetermining the measurement parameter(s) of the invalid object as anunacceptable valid object parameter(s), operatively associated with themeasurement detector(s) and the means for determining from thevalidating parameter(s) whether the object is a valid object.

According to a twenty third embodiment of this invention there isprovided an apparatus for determining a first parameter(s) of a validobject and determining a first parameter(s) of an invalid object,comprising:

the apparatus of the twelfth embodiment;

means for determining the first parameter(s) of the object from themeasurement parameter(s) and for determining the first parameter(s) ofthe valid object as an acceptable valid object parameter(s) and fordetermining the first parameter(s) of the invalid object as anunacceptable valid object parameter(s), operatively associated with themeasurement detector(s) and the means for determining from thevalidating parameter(s) whether the object is a valid object.

Generally, the apparatus of the twelfth embodiment further comprises atleast one of the following items:

(i) means for determining the first parameter(s) of the object from themeasurement parameter(s) operatively associated with the measurementdetector(s);

(k) means for storing the measurement parameter(s) of the objectoperatively associated with the measurement detector(s);

(l) means for storing the first parameter(s) of the object operativelyassociated with the means for determining the first parameter(s);

(m) means for retrieving the measurement parameter(s) of the objectoperatively associated with the means for storing the measurementparameter(s);

(n) means for retrieving the first parameter(s) of the objectoperatively associated with the means for storing the firstparameter(s);

(o) means for storing the validating parameter(s) of the objectoperatively associated with the validating detector(s);

(p) means for retrieving the validating parameter(s) of the objectoperatively associated with the means for storing the validatingparameter(s);

(q) means for storing the object validation operatively associated withthe means for determining whether the object is a valid object;

(r) means for retrieving the object validation operatively associatedwith the means for storing the object validation;

(h') means for determining the measurement parameter(s) of the validobject as an acceptable valid object parameter(s) operatively associatedwith the means for determining whether the object is a valid object andthe measurement detector(s);

(i') means for determining the first parameter(s) of the valid objectfrom the measurement parameter(s) operatively associated with the meansfor determining whether the object is a valid object and the measurementdetector(s);

(j') means for determining the first parameter(s) of the valid object asan acceptable valid object parameter(s) operatively associated with themeans for determining whether the object is a valid object and the meansfor determining the first parameter(s) of the valid object(or theobject);

(k') means for storing the measurement parameter(s) of the valid objectoperatively associated with the means for determining whether the objectis a valid object and the measurement detector(s);

(l') means for storing the first parameter(s) of the valid objectoperatively associated with the means for determining whether the objectis a valid object and the means for determining the first parameter(s)of the valid object(or the object);

(m') means for retrieving the measurement parameter(s) of the validobject operatively associated with the means for determining whether theobject is a valid object and the means for storing the measurementparameter(s) of the valid object (or the object);

(n') means for retrieving the first parameter(s) of the valid objectoperatively associated with the means for determining whether the objectis a valid object and the means for storing the first parameter(s) ofthe valid object(or the object);

(h") means for determining the measurement parameter(s) of the invalidobject as an acceptable invalid object parameter(s) operativelyassociated with the means for determining whether the object is ainvalid object and the measurement detector(s);

(i") means for determining the first parameter(s) of the invalid objectfrom the measurement parameter(s) operatively associated with the meansfor determining whether the object is a invalid object and themeasurement detector(s);

(j") means for determining the first parameter(s) of the invalid objectas an acceptable invalid object parameter(s) operatively associated withthe means for determining whether the object is a invalid object and themeans for determining the first parameter(s) of the invalid object(orthe object);

(k") means for storing the measurement parameter(s) of the invalidobject operatively associated with the means for determining whether theobject is a invalid object and the measurement detector(s);

(l") means for storing the first parameter(s) of the invalid objectoperatively associated with the means for determining whether the objectis a invalid object and the means for determining the first parameter(s)of the invalid object(or the object);

(m") means for retrieving the measurement parameter(s) of the invalidobject operatively associated with the means for determining whether theobject is a invalid object and the means for storing the measurementparameter(s) of the invalid object(or the object);

(n") means for retrieving the first parameter(s) of the invalid objectoperatively associated with the means for determining whether the objectis a invalid object and the means for storing the first parameter(s) ofthe invalid object (or the object).

The means for determining, storing and retrieving the measurementparameter(s) and/or the first parameter(s) may perform such a step(s)prior to or after the determination of the validity of an object.

Advantageously, the validating energy source(s) is the same as themeasurement energy source(s);

the validating energy beam(s) is the same as the measurement energybeam(s) and is an expanding beam of light emerging from a pinholeilluminated by a collimated light beam or is a collimated light beam;

the validation interaction volume(s) is the same as the measurementinteraction volume(s) and is one interaction volume; and

the validating parameter(s) is the intensity from at least part of animage of the interaction volume produced using the validating outgoingenergy, the validating outgoing energy being in the form of light; and

the measurement parameter(s) is the intensity of at least a portion ofthe measurement outgoing energy said measurement outgoing energy being adiffraction pattern.

Generally, the validating energy source(s) is the same as themeasurement energy source(s);

the validating energy beam(s) is the same as the measurement energybeam(s) and is an expanding beam of light emerging from a pinholeilluminated by a collimated light beam or is a collimated light beam;

the validation interaction volume(s) is the same as the measurementinteraction volume(s) and is one interaction volume;

the validating parameter(s) is the intensity from at least part of animage of the interaction volume produced using the validating outgoingenergy, the validating outgoing energy being in the form of light;

the measurement parameter(s) is the intensity of at least a portion ofthe measurement outgoing energy said measurement outgoing energy being adiffraction pattern;

a valid object comprises a fibre selected from the group consisting of asheep wool fibre and goat hair; and

has a preselected length in a preselected position and orientation inthe validation and measurement interaction volume(s) and the firstparameter(s) is the diameter of the fibre.

Typically, the apparatus further comprises

means for determining statistical information in respect of a pluralityof the diameters of the valid object(s).

Typically, the validating outgoing energy is light; and

the apparatus further comprises a light focuser to form an image of thevalidating interaction volume on the validating detector(s), operativelyassociated with the validating source(s) and validating detector(s).

Typically, the measurement outgoing energy is light; and

the apparatus further comprises a light focuser to form an image of themeasurement interaction volume on the measurement detector(s),operatively associated with the measurement source(s) and measurementdetector(s).

Advantageously, the apparatus of the invention may further comprise:

means to pass an object through the measurement and validatinginteraction volumes, operatively associated with the validating energysource(s), measurement energy source(s) and the means for locating.

Typically the light source is a laser.

The apparatus may include a focuser(s) for focussing outgoing energyoriginating from the energy beams in the interaction volumes to provideat least one image of at least a portion(s) of the interaction volumesin the focal plane which image(s) may be a virtual image(s) or a realimage(s), in focus or out of focus at the validating detector(s) and/orthe measurement detector(s).

The validating and measurement means may be the same, may include commonelements or may be different from one another.

The validating and measurement energy sources may be the same, mayinclude common elements or may be different from one another.

The measurement parameter(s) and validating parameter(s) may be the sameor may be different from one another. If they are the same they maydiffer in that they are detected at different precisions, for example.The measurement parameter(s) and validating parameter(s) may both beused to determine the first parameter(s) and/or the objectvalidation(but to different resolutions from one another).

The measurement and validating detector(s) may be the same, may includecommon elements or may be different from one another.

The detection of the validating and measurement outgoing energies maytake place simultaneously, at overlapping times or at different timesand/or the measurement parameter(s) may be used to determine thevalidity of the measurement and/or the validating parameter(s) may beused to determine the first parameter(s).

The validating and measurement interaction volume(s) may be the sameinteraction volume(s), include portions of the same interactionvolume(s), or be different interaction volume(s).

The validating and measurement energy beam(s) may be the same energybeam(s), include portions of the same energy beam(s), or be differentenergy beam(s).

The apparatus of the invention may further comprise:

means for outputting and/or discarding invalid and/or valid firstparameter(s) and/or validating parameter(s) and/or measurementparameter(s) and/or the determination from the validating parameter(s)whether the validating outgoing energy originated from an interactionbetween a valid object and the validating beam(s) in the validatingvolume(s), the means for outputting being operatively associated withthe means for determining the first and/or validating parameter(s)and/or the means for storing the measurement parameter(s) and/or thefirst and/or validating parameter(s) and/or the validating and/ormeasurement detector(s).

The outputting may be in the form of an information signal orinformation display, for example. Examples of information signals orinformation displays include written text, on paper, electronic displayscreens (LCD screens, electroluminescent screens, gas plasma screens,video monitors, for example) digital or analogue electronic signals,acoustic signals, magnetic signals, electromagnetic signals, forexample.

The apparatus of the invention may include:

means for determining statistical information in respect of a pluralityof measurement and/or first and/or validating parameter(s), and/orobject validations operatively associated with the means for determiningthe first and/or validating parameter(s) and/or the means for storingthe measurement parameter(s) and/or the first and/or validatingparameter(s) and/or the validating and/or measurement detector(s).

Examples of statistical information include mean, standard deviation,coefficient of variation, variance, skewness, kurtosis, and othermoments about the mean, spline fits, line fits including linear,exponential, logarithmic, multiple and polynomial regressions, fractalfitting, mode, median, distribution fits including normal, gaussian,fermi, poisson, binomial, Weibull, parabolic, frequency, probability,cumulative and top hat distributions, data smoothing including runningmedians, means and least squares, table formation such as histograms andtwo way contingency, data manipulation for graphs, forecasting,probability statistics, simulations, pattern recognition, t test, chisquare test, sample size, Wilcoxon signed-rank test, rank sum test,Kolmogorov-Smirnov test and boundary value and limit statistics. A moredetailed description of statistical techniques is disclosed in G. E. P.Box, W. G. Hunter and J. S. Hunter, Statistics for Experimenters, JohnWiley & Sons, Inc, New York, U.S.A., 1978, the contents of which areincorporated herein by cross reference.

Generally, multiple focal planes of the outgoing energies are detected.

A valid object must have a measurable parameter(s) which can bevalidated. Examples of such measurable parameter(s) include a validshape, diameter, area, chemical composition, colour, number of parts,thickness, width, length, absorptivity, reflectivity, transmittivity,dielectric constant, Raman scattering profile, fluorescence, surfacetexture or other surface detail, position, orientation, surface tension,surface roughness, surface profile or density, for example in the easeof a fibrous object for example where the first parameter is diameter,for example a valid object may be one in which a single fibre fullytraverses the centre of the validating and measurement beam(s)(which maybe the same beam) in the validating and measurement volume(s)(which maybe the same volume).

The first parameter(s) may be shape, diameter, area, chemicalcomposition, colour, number of parts, thickness, width, length,absorptivity, reflectivity, transmittivity, dielectric constant, Ramanscattering profile, fluorescence, surface texture or other surfacedetail, position, orientation, surface tension, surface roughness,surface profile or density, for example. In the case of a fibrous objectfor example the first parameter may be diameter, for example.

A valid first parameter(s) measuring position and orientation may bewhen an object fully crosses the centre of the energy beam(s) andwithout another object being in the energy beam(s). The validation maybe false if there is no object in the interaction volume(s) or if thereis more than one object in the energy beam(s) in the interactionvolume(s) or if the object does not intersect the energy beam(s) fullyin the interaction volume(s) or if the object in the energy beam(s) inthe interaction volume(s) is not a single bodied object, for example.

The energy source(s) may be coherent, partially coherent or incoherentand can provide a solid particle beam, such as a neutron, proton orelectron beam or a beam of alpha particles, acoustic waves, such assound waves, or electromagnetic radiation, such as gamma rays, x-rays,UV light, visible light, infrared light or microwaves. Generally theenergy source is a source of electromagnetic radiation with a wavelengthin the range of and including far IJV to far IR.

Examples of light sources include incandescent sources, such as tungstenfilament source, vapour lamps such as halogen lamps including sodium andiodine vapour lamps, discharge lamps such as xenon arc lamp and a Hg arelamp, solid state light sources such as photo diodes, super radiantdiodes, light emitting diodes, laser diodes, electroluminescent lightsources, frequency doubled lasers, laser light sources including raregas lasers such as an argon laser, argon/krypton laser, neon laser,helium neon laser, xenon laser and krypton laser, carbon monoxide andcarbon dioxide lasers, metal ion lasers such as cadmium, zinc, mercuryor selenium ion lasers, lead salt lasers, metal vapour lasers such ascopper and gold vapour lasers, nitrogen lasers, ruby lasers, iodinelasers, neodymium glass and neodymium YAG lasers, dye lasers such as adye laser employing rhodamine, 640, Kiton Red 620 or rhodamine 590 dye,and a doped fibre laser.

The energy source may be a pinhole energy source. The energy source maycomprise an energy fibre, the exit end of which may effectively act as apinhole source.

The energy beam(s) may be collimated, diverging or converging.

The energy beam(s) in the interaction volume(s) may take the form of adiffraction pattern(s).

The outgoing energy may be transmitted and/or redirected energy.

The outgoing energy may include an interacted and/or uninteractedportion of the energy beam(s).

The outgoing energy where it intersects the validation detector may be aportion of the diffraction pattern resulting from the occlusion of theenergy beam(s) by a portion of an object in the interaction volume(s).

If the source is a pinhole source and the energy beam(s) is thediffraction pattern resulting from the passage of energy through thepinhole, the outgoing energy in a focal plane may take the form of theoptical superposition of the diffraction pattern resulting from thepinhole and the diffraction pattern resulting from interaction betweenthe energy beam(s) and a portion of the object in the interactionvolume(s).

The apparatus may include means to pass the object through theinteraction volume(s), the means to pass being operatively associatedwith the means for locating. The means to pass may be a sample carriersuch as a conveyer strip, a sample holder on a linear or rotary stage ora fluid stream (fluid including liquids and gases), for example. Thefluid stream may be confined by a cell which cell is used to orientateobjects therein. The interaction volume(s) may be defined by theintersection of the central portion of the energy beam(s) and the cell.The cell may be of the type described in Australian Patent No. 472,862the contents of which are incorporated heroin by cross reference and/orAustralian Patent No. 599,053 the contents of which are incorporatedheroin by cross reference.

The apparatus may comprise a scanner operatively associated with theenergy source(s) and/or the object and/or the sample carrier to scan theenergy beam relative to the object in the interaction volume(s). Thescanner may be a piezoelectric stack, a magnetic core/magnetic coilcombination, a mechanical vibrator, an electromechanical vibrator, amechanical or electromechanical scanning mechanism such as a servomotor,an acoustic coupler electrooptic scanning means or any other suitablemeans.

The energy source(s) may include a first energy deflector locatedbetween the source and the interaction volume(s) wherein a portion ofthe energy beam(s) passes through the first deflector and whereby thefirst deflector is operatively associated with the source to alter theshape, size, wavelength, intensity, polarisation, phase, direction oftravel or focus of at least a portion of the energy beam(s) in theinteraction volume(s).

There may be disposed in the path of the outgoing energy between theinteraction volume(s) and the validation detector and/or the measurementdetector, a second energy deflector wherein the outgoing energy passesthrough the second deflector which alters the size, shape, intensity,polarisation, phase, direction of travel, focus or wavelength, forexample. The second energy deflector may split the validating andmeasurement outgoing energy.

The first and second energy deflectors may include energy focusers orenergy reflectors.

The focuser may be refractive lenses, including microscope objectives,reflective lenses, and/or holographic optical elements. If the energy isof a frequency other than in the range of UV to near infrared light orother types of energies, analogous focussing elements are used in placeof the optical focussing elements.

The reflector may be a mirror or partially silvered mirror, a beamsplitter including a polarisation dependent beam splitter, energywaveguide splitter (eg an optical fibre coupler) or a wavelengthdependent beam splitter, for example. The optical fibre coupler may be afused biconical taper coupler, a polished block coupler, a bottled andetched coupler or a bulk optics type coupler with fibre entrance andexit pigtails, a planar waveguide device based on photolithographic orion-diffusion fabrication techniques or other like coupler.

The object may be a fluid or solid or other of matter. Examples ofobjects include mineral objects, such as diamonds and other crystals,organic and inorganic contaminants, fibrous objects, randomly shapedobjects, spherical objects or cylindrical objects. Generally the objectsare fibrous objects or woven or twisted fibrous objects. The fibrousobjects may be synthetic fibres or natural fibres. The fibres may befibreglass fibres, hessian fibres, nylon fibres, glass fibres, polnosicand polyester fibres, abaca fibres, silk fibres, jute fibres, flax andcellulose fibres (including paper, recycled paper, corn stalks, sugarcane, wood, wood shavings, bagasse, wood chips), regenerated fibres suchas viscose, rayon, cuprammonium rayon and cellulose acetate, sisalfibres, carbon fibres, stainless steel fibres, vegetable fibrousmaterial, polyolefin fibres such as polyethylenes and polypropylene,steel fibres, boron fibres, copper fibres, brass fibres, teflon fibres,dacron fibres, mylar fibres, aluminium fibres, aluminium alloy fibres,polyamide fibres, polyacrylic fibres, or absorbent fibres such as nylon66 polyacrylonitrile, or polyvinyl alcohol and absorbent types ofpolyesters or polyacrylics, edible vegetable fibres, such as wheatfibres, or inedible vegetable fibres, such as wood pulp or cottonfibres, animal fibres, such as meat fibres, wool fibres such as woolfibres from sheep, hairs, such as human hairs, goat hairs, cattle hairs,or feathers, yarns including wool and cotton yarns, string, wire,optical fibres for example.

Typically, a valid object comprises a fibre selected from the groupconsisting of a fibreglass fibre, hessian fibre, nylon fibre, glassfibre, polnosic fibre, polyester fibre, abaca fibre, silk fibre, jutefibre, flax fibre, cellulose fibre, regenerated fibre, sisal fibre,carbon fibre, stainless steel fibre, vegetable fibre, polyolefin fibre,steel fibre, boron fibre, copper fibre, brass fibre, teflon fibre,dacron fibre, mylar fibre, aluminium fibre, aluminium alloy fibre,polyamide fibre, polyacrylic fibre, nylon 66 polyacrylonitrile fibre,polyvinyl alcohol fibre, edible vegetable fibre, inedible vegetablefibre, wood pulp fibre, cotton fibre, animal fibre, meat fibre, sheepwool fibre, hair, human hair, goat hair, cattle hair, yarn, wool yarn,cotton yarn, string, wire and optical fibre.

Generally, a valid object has a preselected length in a preselectedposition and orientation in the validation and measurement interactionvolume(s).

The measurement and/or validation detector(s) may comprise an array ofdetecting elements and/or apertures. An aperture in the array may be anenergy entrance portion of an energy guide operatively associated withthe validating and/or measurement focal plane(s) to collect a portion ofthe outgoing energy and guide it to the measurement and/or validationdetector(s). A detecting element in the array may be photodiode,photomultiplier, part of a ccd array or the like.

The array may be a three dimensional array or a planar array.

The outgoing energy may be a beam and the array may be symmetric aboutthe central axis of the beam. The array may be a linear, square,rectangular, circular, hexagonal, spiral, spherical, cubic or randomarray, for example. Some of the apertures or detecting elements in thearray may be elongated, round, elliptical, square, rectangular,triangular, hexagonal, rhomboid or random in shape, for example.

The apertures or detecting elements may be movable or fixed with respectto the validating focal plane and/or the measurement focal plane and/orthe measurement and/or validating interaction volume(s).

The energy guide may be a slab waveguide. The slab waveguide can be asingle mode slab waveguide.

The energy guide can be an energy fibre.

The energy guide can be a multi mode optical fibre.

The energy guide can be a single mode optical fibre. For example, a fourmicron core fibre which is single mode at a wave length of 633nanometers given an appropriate refractive index profile. A step indexoptical fibre becomes single mode when the numerical aperture, NA, thefibre core radius, a, and the wave length of light, λ, obey therelationship:

    2×π×NA×a/λ≦2.405,

more typically

    2×π×NA×a/λ≦0.6.

The energy guide may be a fibre bundle.

The optical fibres may include glass or plastic elements or acombination of these.

Portions of the source and detector energy guides may be portions of thesame energy guide.

The validating detector(s) and/or the measurement detector(s) maycomprise an array of detecting elements.

When the validating outgoing energy is light the validating detector(s)may comprise an optical fibre(s) coupled to a detecting element(s).

When the measurement outgoing energy is light the measurementdetector(s) may comprise an optical fibre(s) coupled to a detectingelement(s).

The validating detector(s), the measurement detector(s), the means todetermine the first parameter(s), and/or validating means and/or meansfor locating may comprise a calculator which may include optical,electrical, optoelectronic, mechanical or magnetic elements, forexample, or may include such techniques as optical and/or electricalheterodyning, quadrature operation, multi area detectors or phase lockloop techniques, for example. The means for determining the firstparameter(s) may log and analyse a signal(s) from the measurementdetector(s) and/or validation detector(s) or may log and analyse thefirst parameter(s) and/or validating parameter(s) and/or the measurementparameter(s) and/or the object validation. The means for determining thefirst parameter(s) typically includes a computer.

The means for locating may comprise a timer and/or a counter.

The interaction is typically one or a combination of refraction,diffraction, reflextion, scattering, fluorescence, stimulated emission,incandescence, shadowing, polarisation rotation, phase retardation andother polarisation effects, occlusion, optical absorption, interferenceeffects, sum frequency generation, one giving rise to a diffractionpattern, refraction, phase alteration, second, third or fourth harmonicgeneration, difference frequency generation, optical bistability, selfbleaching, Raman scattering or Brillouin scattering. A nonlinearreaction can be involved as a result of heating, refractive indexchange, charge build-up or charge migration.

The first parameter(s) and the measurement parameter(s) may be the sameor may include some of the same elements or they may be different fromone another.

The validating parameter(s) and the measurement parameter(s) may beenergy intensity(including spatially or temporally dependent intensitypatterns such as images or intensity peaks or troughs as or not as afunction of time), amplitude, wavelength or frequency modulation, phase,polarisation, wavelength, direction of travel, for example.

The apparatus of the invention may include:

a mask to mask off a portion of the validating and/or measurement and/orvalidating outgoing and/or measurement outgoing beams.

For the purposes of this specification planes of focus includediffraction planes at different distances from an object whether real orapparent(as a result of a focuser, for example). Note that an in focusimage of an object is the diffraction plane in the plane of the object,but may be magnified or reduced. Note also that a focuser may be used tocreate a virtual as opposed to a real image.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 schematically depicts an apparatus for determining a the mean andstandard deviation of a plurality of diameters of wool fibres, inaccordance with the invention;

FIG. 2 schematically depicts an alternative apparatus for determining athe mean and standard deviation of a plurality of diameters of woolfibres, in accordance with the invention;

FIG. 3 schematically depicts in detail the processor in the apparatus ofFIG. 1;

FIG. 4 schematically depicts the geometry for the apparatus of FIG. 1;

FIG. 5 schematically depicts in detail the processor/timer in theapparatus of FIG. 1;

FIG. 6(a) is a typical reverse image of a 15 micrometer diameter woolfibre in the plane of end 107 of apparatus 100 of FIG. 1;

FIG. 6(b) is a typical reverse image of a 15 micrometer diameter woolfibre in the plane of detector 118 of apparatus 100 of FIG. 1;

FIGS. 7(a)-(d) show typical signals passed by comparator 113e to statemachine 113f via line 114f of processor/timer 113 of FIG. 5 of apparatus100 of FIG. 1.

BEST MODE AND OTHER MODES FOR CARRYING OUT THE INVENTION

Referring to FIG. 1 an apparatus 100 for determining the mean andstandard deviation of a plurality of diameters of wool fibres, includesa validating and a measurement laser light source, namely He-Ne laser101, and a 276 micrometer diameter pinhole 102 which form a pinholediffraction validating and measurement expanding laser beam which passesthrough a validating and measurement interaction volume defined by theintersection of the central diffraction spot and first diffraction ringof the expanding laser beam and tapered cell 105 oriented not normal tothe direction of travel of the expanding laser beam. The optical pathlength between the center of cell 105 and pinhole 102 is 90 mm.Polarisation independent beam splitter 103 is operatively disposed topinhole 102 and laser 101 to direct a portion of the expanding laserbeam to 1 mm diameter reference detector 109 which is electricallyconnected to processor 110 via line 111. The optical path length betweenpinhole 102 and detector 109 is 208 mm. When apparatus 100 is operatingwool fibres in an isopropanol-wool slurry pass through cell 105generally at a non-zero degree angle to the direction of slurry flowthrough cell 105 to scatter, reflect, diffract, absorb, refract andotherwise interacts with the expanding laser beam in the interactionvolume from laser 101. A detailed description of cell 105 is containedin Australian Patent no. 599 053. Polarisation independent beam splitter104 and microscope objective 106 are operatively disposed with respectto laser 101, pinhole 102 and cell 105 to produce, using validatingoutgoing light from the interaction volume, an in focus magnifiedtransmission image of wool fibres in the validating and measurementinteraction volume in the plane of end 107 of 18 optical fibre ringbundle 108 comprising at end 107 a central fibre surrounded by a 2.597mm diameter ring of 16 plastic optical fibres each having a 0.5 mmdiameter core and a 10 micrometer thick cladding and a single modefibre. The optical path length between the centre of cell 105 and thefront principal plane of objective 106 is 42.4 mm and the optical pathlength between the back principal plane of objective 106 and end 107 is228.2 mm so the image from the centre of cell 105 is magnified by 5.4times at end 107. Each of the plastic fibres in bundle 108 is connectedto a photodiode detector in an the array of 17 photodiode detectorscomprising validating detector 112 for detecting the light intensitypassing through each of the fibres in bundle 108 from validatingoutgoing energy originating from the validating and measurement beam inthe interaction volume. Processor/timer 113 is connected electrically todetector 112 by line 114. Processor/timer 113 is also connectedelectrically to computer 115 by line 116 and to processor 110 by line117. One mm diameter split detector 118 is connected electrically toprocessor 110 by line 119. Processor 110 is connected electrically tocomputer 115 by line 120. Detector 118 is operatively disposed withrespect to laser 101, pinhole 102 and cell 105 to detect measurementoutgoing light which is in the form of a diffraction pattern. Theoptical path length between the centre of cell 105 and detector 118 is118 mm.

Referring to FIG. 4, which schematically depicts the geometry forapparatus 100, the observed diffraction pattern intensity at splitdetector 118, resulting from pinhole 102 of diameter D and a wool fibreof diameter d at the plane of cell 105 is given by ##EQU1##

In equations (2) to (5) A(v+p) is the illumination field amplitude inthe plane of cell 105. The equivalent normalised position on detector118 is given by

    v=x/√[(1+b/a)b.λ/2],                         (6)

the normalised wool fibre diameter is

    Δv=d√[2(a+b)/a.b.λ],                   (7)

a is the optical path length between from pinhole 102 and the centre ofcell 105, b is the optical path length between the centre of cell 105and detector 118 and λ is the wavelength of the light from laser 101.

As pinhole 102 is substantially uniformly illuminated by laser lightfrom laser 101, the illumination field amplitude at the plane of thecentre of cell 105 is circularly symmetric and is given by

    A(x,y)=2 J.sub.1 (z)/z                                     (8)

where J₁ (z) is the first order Bessel function of the first kind and

    z=(π.D/(a+b)λ).√(x.sup.2 +y.sup.2)        (9)

To calculate the diffraction pattern intensity I(v)|_(y=y) of equation(1), along any off-axis line y=y, equation (8) is used to calculate theFraunhofer field amplitude appearing in equations (2)-(5).

In order to obtain geometrically similar configurations of apparatus 100for different optical systems, the diffraction pattern at detector 118must scale identically with the change in detector size for the twoconfigurations for any given wool fibre. If the radius of detector 118for the new apparatus 100 (denoted by dashed variables) is related tothe old detector 118 radius R by

    R'=kR                                                      (10)

then to get geometric similarity

    b'=kb                                                      (11)

    a'=k.b/[(1+b/a)k-1]                                        (12)

    D'/D=(a'+b')/(a+b).k                                       (13)

Equations (10), (11), (12) and (13) thus define a new apparatus 100,which is geometrically similar to the old and thus responds in exactlythe same way when a wool fibre passes through the interaction volume.For example, suppose apparatus 100 with detector 118 of radius R=0.5 mm,D=276.5 micrometers and with (a,b)=(90,118) mm is replaced with a newdetector 118 of radius R'=1 mm. The scaling factor is now k=2 and thenew cell 105 and detector 118 planes must be located at (a',b')=(65,235)mm, while the new pinhole 102 diameter is D'=200 micrometers, for thenew apparatus 100 to have the same response as the old one.

For the two geometries outlined above, there is an apparent change inwool fibre diameter with the position of the wool fibre along the axisof the expanding laser beam. Thus, because cell 105 has a finite width,typically 2 mm, there is an uncertainty in the measured diameter. Thisuncertainty is typically +/-1.9% for a 30 micron fibre. However, theapparatus of FIG. 1 may be rescaled so that there is no substantialapparent diameter change with axial position of wool fibres along theaxis of the expanding laser beam. This can be done by making a=b or aand b tend to infinity or R tend to 0. Thus, for an arrangement that isgeometrically similar to the two described above, one might puta'=b'=101.9 mm, D'=313.3 micrometers and R'=0.434 mm.

If a substantial amount of interacted light is collected by detector118, then diameter independent parameters such as wool fibre medulationand colour as well as position and orientation, for example may affectthe diameter determination and thus the accuracy of the measurement.Thus in apparatus 100, detector 118 is placed with respect to cell 105so as to not collect so much light from the interaction volume that hasinteracted with a wool fibre in cell 105 to prevent determination of thediameter of the wool fibre to within the required accuracy. Detector 118may be placed closer to cell 105, at the expense of accuracy, but foroptimum accuracy should be positioned as far as possible from cell 105to minimise effects from diameter independent parameters on the woolfibre diameter determination. Because of the nature of the expandingbeam from pinhole 102, there is a practical limitation on the upperlimit of separation between cell 105 and detector 108. A alternativepractical apparatus for measuring fibre diameter independent of woolfibre diameter independent parameters, in which the measurement detectoris located at an effective infinite distance from the interaction volumeis described below with reference to FIG. 2.

End 107 is centred in the image of the pinhole diffraction in theinteraction volume by maximising the light intensity collected by thecentral fibre. The image of the pinhole diffraction in the interactionvolume is bought into focus at end 107 by positioning end 107 so thatthe light intensity signal collected by the single mode fibre in bundle108 substantially approximates a top hat profile when a wool fibrepasses through cell 105. Generally the fibres in the ring at end 107 arepacked closely to one another to minimise the separations between them.The magnification of the interaction volume at end 107 is such that the16 0.5 mm optical fibres in the ring of bundle 108 at end 107 arelocated just outside the first minimum of the pinhole diffractionpattern of the image at end 107 to capture light from the firstdiffraction ring. If different diameter optical fibres are chosen or thenumber of fibres in the ring is changed, for example, the position ofobjective 106 with respect to cell 105 and end 107 is adjusted such thatthe optical fibres in the ring of bundle 108 at end 107 are located justoutside the first minimum of the pinhole diffraction pattern of theimage at end 107.

Since the image of wool fibres in the interaction volume at end 107 isin focus, information about the position and orientation of the woolfibres is readily obtainable from the image. If end 107 is moved fromthe position of the in focus image of the interaction volume theposition and orientation of the wool fibres may be less readilyobtainable.

As depicted schematically in FIG. 5, processor/timer 113 comprisescurrent to voltage converter 113a electrically connected to detector 112by line 114 and to amplifier 113b by line 114a. Amplifier 113b iselectrically connected to three pole butterworth filter 113c via line114b and analogue divider 113d by line 114d. Analogue divider 113d isalso electrically connected to comparator 113e by line 114e and filter113c via line 114c. Comparator 113e is electrically connected to statemachine 113f via line 114f. State machine 113f is identified as a meansfor locating for determining that the wool fibre that interacted withthe expanding laser beam in the interaction volume to give rise tovalidating outgoing energy is the same wool fibre that gave rise to themeasurement outgoing light for the current measurement. State machine113f is electrically connected to timer 113g via line 114g, countdowntimer 113h via line 114h, magnitude comparator 113j via line 114i, multistorage device 113k via line 114k, computer 115 via line 116a and line116 and processor 110 via line 117. Multistorage device 113k iselectrically connected to computer 115 by line 116.

As depicted schematically in FIG. 3, processor 110 comprisesamplifier/divider/offsetter 110a electrically connected to detector 109by line 111, detector 118 by line 119, calculator 110f by line 119g andscaler/inverter 110b by line 119a. Scaler inverter 110b is electricallyconnected to threshold detector 110c by line 119c and peak detector 110dby line 119b. Threshold detector 110c is electrically connected toprocessor/timer 113 by line 117, computer 115 by line 120a and line 120,peak counter 110e by line 119d and peak valid storage 110h by line 119e.Peak detector 110d is electrically connected to processor/timer 113 vialines 117a and 117, peak counter 110e by line 119f, calculator 110f byline 119j and measurement storage 110g by line 119h. Peak counter 110eis electrically connected to computer 115 by lines 120b and 120,calculator 110f is electrically connected to peak valid storage 110h byline 119i, peak valid storage 110h is electrically connected to computer115 by lines 120c and 120 and measurement storage 110g is electricallyconnected to computer 115 by tines 120d and 120.

In operation, a method for determining the mean and standard deviationof a plurality of diameters of wool fibres, includes passing avalidating and measurement laser beam from laser 101 through pinhole 102and via splitter 103 to form a pinhole diffraction pattern in theinteraction volume in cell 105 and a reference pinhole diffractionpattern in the plane of reference detector 109 which detects theintensity of the reference pinhole diffraction pattern to produce areference signal. The reference signal from detector 109 is passed toprocessor 110 via line 111 where it is amplified byamplifier/divider/offsetter 110a to produce an amplified referencesignal. The periphery of detector 109 is in about the same position asthe first minimum of the reference pinhole diffraction pattern. In theevent that there is no wool fibre in the interaction volume, a baselinepinhole diffraction pattern is formed in the plane of detector 118 whichis detected by detector 118 to produce two baseline signals, designatedbaseline signals Ab and Bb. The baseline signals from the top and bottomhalves of detector 118 are separately passed to processor 110 by line119, amplified and divided by the amplified reference signal, obtainedat the same time, by amplifier/divider/offsetter 110a, to producenormalised baseline signals Abn and Bbn. The periphery of detector 118is in about the same position as the first minimum of the baselinepinhole diffraction pattern. The sum of the normalised baseline signalsAbn+Bbn is offset to zero by the amount BL byamplifier/divider/offsetter 110a. A wool fibre in the isopropanol-woolslurry is passed through the interaction volume to produce measurementoutgoing light which is in the form of a diffraction pattern comprisingthe optical superposition of the pinhole diffraction pattern and thediffraction pattern produced by the interaction of the wool fibre andthe expanding laser beam in the interaction volume, the measurementoutgoing light passing through splitter 104 and being detected bydetector 118 to produce two measurement signals from the top and bottomhalves of split detector 118, designated measurement signals Am and Bm.The measurement signals from detector 118 are separately passed toprocessor 110 by line 119, amplified and divided by the amplifiedreference signal, obtained at the same time, to produce normalisedmeasurement signals Amn and Bmn which are made available to calculator110f via line 119g.

The sum of the normalised measurement signals Amn+Bmn is offset by BL byamplifier/divider/offsetter 110a and passed to scaler/inverter 110b vialine 119a. Scaler/inverter 110b scales and inverts the signal to producea measurement signal M where the scaling allows M to remain within thedynamic range of processor 110 for the largest diameter fibre to bemeasured corresponding to a largest allowed measurement signal Mm. Thevalue M is passed to threshold detector 110c via line 119c and peakdetector 110d via line 119b.

When threshold detector determines that the measurement signal M exceedsa threshold of typically 1%-10% of Mm, an above threshold signal ispassed to processor/timer 113 via line 117, a peak valid signal Vp inpeak valid storage 110h is set to "FALSE" via line 119e and peak counter110e is set to zero via line 119d. As the wool fibre passes through theinteraction volume, measurement signal M passes through a maximum due tothe occlusion of the expanding laser beam in the interaction volume bythe wool fibre which maximum is peak detected by peak detector 110d,typically within 100 microseconds, more typically within 5 microsecondsof the peak, upon which peak counter 110e is incremented via line 119f,a peak detect signal is sent to processor/timer 113 via lines 117a and117, the maximum value Mp of measurement signal M is passed tomeasurement storage 110g via line 119h, measurement storage 110g storesMp, the values Amn and Bmn are accepted by calculator 110f fromamplifier/divider/offsetter 110a via line 119g as directed by peakdetector 110d via line 119j, calculator 110f calculates result|(Amn-Bmn)|, which value may be indicative of whether the wool fibrefully traversed the interaction volume at the time of the peak. If theresult is less than typically 10%, more typically 3% of the value of Mp,calculator 110f sets the peak valid signal Vp in peak valid storage 110hto "TRUE" via line 119i. If peak detector 110d detects a second peak inmeasurement signal M while M remains above threshold, peak counter 110eis incremented a second time via line 119f.

When threshold detector 110c detects that the measurement signal M fallsbelow threshold, it sends a data available signal to computer 115 vialines 120a arid 120 upon which computer 115 reads the peak value of themeasurement signal Mp stored in measurement storage 110g via lines 120dand 120, the peak valid signal Vp stored in peak valid storage 110 vialines 120c and 120 and the value stored in peak counter 110e via lines120b and 120.

Validating outgoing light from the interaction volume is deflected bysplitter 104 and focussed by objective 106 to produce an in focusmagnified transmission image of the wool fibre in the interaction volumein the plane of end 107 of bundle 108. Light falling on the cores offibres in bundle 108 at end 107 is guided to the array of 17 photodiodedetectors of detector 112. Each of the 17 photodiode detectors detectsthe intensity of light guided by its corresponding fibre in bundle 108to produce an output signal which is fed to current to voltage converter113a via line 114. Converter 113a produces output voltages proportionalto each of the light intensity detected by the corresponding photodiodesof detector 112. Each output voltage is passed to amplifier 113b vialine 114a. Amplifier 113b amplifies and limits the bandwidth of eachoutput voltage to produce amplified signals which are passed to theinputs of three pole butterworth filters 113c via line 114b and thenumerator input of analogue dividers 113d via line 114d. Filter 113cgenerates low frequency (substantially DC) signals that track thebaseline intensities detected by the corresponding photodiodes indetector 112. The output of each butterworth filter in falter 113c ispassed to the denominator input of analogue dividers 113d via line 114c.The function of each analogue divider in divider 113d is to normaliseeach signal detected in detector 112 so that each of these signals canbe compared to a common voltage reference in comparator 113e. Thus thenormalisation process carried out by circuits 113a, 113b, 113c and 113dallows for variations between fibres in bundle 108. If this was not donefibre bundle 108 would be extremely difficult and costly to manufactureand mount. The normalised output of each analogue divider in divider113d is fed to comparator 113e via line 113e. Comparator 113e comparesthe normalised output signal levels from divider 113d via line 114e witha voltage reference to produce a 17 bit binary data word representativeof the image focussed onto the fibres at end 107.

The binary word is passed from circuit 113e to a change detectioncircuit, comprising state machine 113f electrically connected tomagnitude comparator 11L3j via line 114i. The function of the changedetection circuit is to detect and latch any change from the currentbinary word passed from comparator 113e via line 114f which occurswhenever there is a significant change in the image focussed by lens 106on end 107.

Before an above threshold signal is fed to state machine 113f, via line117, computer 115 enables state machine 113f via lines 116 and 116a andstate machine 113f resets a memory storage pointer in multi storagecircuit 113k, via line 114k to the beginning of storage circuit 113k.State machine 113f begins the data gathering process when an abovethreshold signal is received from processor 110 via line 117. At thestart of the data gathering process timer 113g is reset by state machine113f via line 114g and begins counting and a busy flag is set in statemachine 113f which busy flag can be monitored by computer 115 via lines116a and 116. During the data gathering process, state machine 113fstores the first binary word as a binary value in an input register. Thecontents of this register are compared to the current binary word usingmagnitude comparator 113j and line 114i. State machine 113f detects aninequality in comparator 113j via line 114i and assembles the change inthe data word from comparator 113e, along with the time read from timer113g via line 114g, sends it to multi storage circuit 113k via line114k, increments the memory storage pointer in multi storage circuit113k, via line 114k and stores the new word in the input register whichremoves the inequality in magnitude comparator 113j. When the peakdetect signal is received by state machine 113f from processor 110 vialine 117, countdown timer 113h is started via line 114h. The countdowntimer typically runs down in 60 micro seconds, which is detected bystate machine 113f via line 114h upon which a last data word fromcomparator 113e via line 114f and corresponding time from timer 113g vialine 114g is assembled by state machine 113f and sent to multistorage113k via line 114k, the data gathering process is stopped and the busyflag is cleared.

Computer 115 monitors the data busy flag from state machine 113f vialines 116 and 116a to determine whether data is available for readingand processing. If computer 115 receives the data available signal fromthreshold detector 110c via lines 120a and 120, it reads the maximumvalue of the measurement signal Mp from measurement storage 110g vialines 120d and 120, the peak valid signal Vp from peak valid storage110h via lines 120c and 120 and the value stored in peak counter 110evia lines 120b and 120. Computer 115 then reads the data words and timesstored in multi storage 113k via line 116 in reverse order, monitoringthe times, until the time monitored is less than a calculated value. Thecalculated value is a predetermined amount, typically 120 microseconds,less than the first time stamp read in by computer 115. For example, ifthe data gathering process was stopped at a time stamp of 160microseconds, computer 115 would typically stop reading data when thetime stamp monitored was less than 40 microseconds.

After reading in the data, computer 115 determines from the value of thepeak valid signal Vp and the number of counts stored in the peak counterwhether one wool fibre may have completely spanned the interactionvolume to give rise to the maximum value of the measurement signal Mp.If so computer 115 confirms, from the data words read in, whether onewool fibre completely spanned the interaction volume about the time Mpwas determined and stored. If the confirmation is true, computer 115calculates the diameter of the wool fibre from Mp using a calibrationlook up table and stores it in its memory.

Apparatus 100 repeats the above procedure and thereby determines fromresultant stored wool fibre diameters the mean and standard deviation.

A typical reverse image of a 15 micrometer diameter wool fibre in theplane of end 107 is depicted in FIG. 6(a). A typical reverse image of a15 micrometer diameter wool fibre in the plane of detector 118 isdepicted in FIG. 6(b). Note that the image of FIG. 6(a) shows featuresposition, orientation, medulation and colour of the wool fibre whereasthe image of FIG. 6(b) does not distinguish such features. FIGS.7(a)-(d) show typical signals passed by comparator 113e to state machine113f via line 114f. FIG. 7(a) results from a valid wool fibre, that is,a wool fibre in a valid position and orientation that completely crossesthe interaction volume such as the wool fibre depicted in FIG. 6(a).FIG. 7(b) results from an invalid object, namely a wool fragment thatdoes not completely cross the interaction volume, passing through theinteraction volume. FIG. 7(c) results from an invalid object, namely twowool fibres that pass through the interaction volume simultaneously.FIG. 7(d) results from an invalid object, namely a wool fibre that doesnot completely cross the interaction volume, passing through theinteraction volume.

Referring to FIG. 2 an apparatus 200 for determining the mean andstandard deviation of a plurality of diameters of wool fibres, includesa validating and measurement optically isolated laser diode 201 whichinjects validating and measurement laser light into the core of singlemode fibre 202. Fibre 202 is optically connected to single mode coupler209 having ports 203, 204, 205 and 206. Port 205 of coupler 209 isoptically connected to single mode fibre 207 having exit end 208. Port204 of coupler 209 is optically connected to photodiode 211 by fibre210. Photodiode 211 is electrically connected to laser diode powersupply 213 by line 212. Supply 213 is electrically connected to laser201 by line 214. Port 206 of coupler 209 is optically connected tomeasurement photo diode 216 by fibre 215. Diode 216 is electricallyconnected to computer 218 by line 217. Collimating lens 219 collimatesvalidating and measurement laser light emerging from the core of fibre207 at end 208 to form a collimated validating and measurement laserbeam typically about 350 micrometers in diameter having an approximatelygaussian intensity profile. The collimated laser beam passes through avalidating and measurement interaction volume defined by theintersection of the beam and tapered cell 220 which is oriented notnormal to the direction of travel of the collimated beam. A detaileddescription of cell 220 is contained in Australian Patent no. 599 053.When apparatus 200 is operating wool fibres in an isopropanol slurrypass through cell 220 generally at a non-zero degree angle to thedirection of slurry flow through cell 220 to scatter, reflect, diffract,absorb, refract and otherwise interact with the collimated beam. Partialmirror 221 reflects measurement outgoing light from the interactionvolume, a portion of which is reinjected into end 208 of fibre 207 to bedetected by diode 216. Partial mirror 221 transmits validating outgoinglight from the interaction volume. Lens 222 is operatively disposed withrespect to end 208, lens 219 and cell 220 to produce, using validatingoutgoing light transmitted by partial mirror 221, a highly visiblediffraction pattern from wool fibres in the interaction volume in theplane of end 223 of 12 400 micrometer glass cored 12.5 micrometer thickplastic clad fibre bundle 224 comprising at end 223 a close packedcircularly symmetric core configuration. Bundle 224 is opticallyconnected to validating detector and neural network 225 which iselectrically connected to computer 218 by line 226. Sample carrier 229is mechanically attached to mechanical stage 228 which is electricallyconnected to computer 218 by line 227.

In operation, a method for determining the mean and standard deviationof a plurality of diameters of wool fibres, includes guiding validatingand measurement laser light from diode 201 to end 208, via fibre 202,ports 203 and 205 of coupler 209 and fibre 207, from which it emergeswith a numerical aperture of typically 0.1. Lens 219 collimates thevalidating and measurement light emerging from end 208 to form acollimated validating and measurement beam which passes through cell220. In the event that there is no wool fibre in the interaction volume,the collimated beam passes through cell 220 and is partially reflectedas uninteracted measurement light by partial mirror 221 back throughcell 220. The uninteracted measurement light, still collimated, isfocussed by lens 219 and injected into the core of fibre 207 at end 208and enters coupler 209 via fibre 207 and port 205. A portion of theuninteracted measurement light entering coupler 209 leaves coupler 209by port 206 to be guided by fibre 215 to diode 216 where it is detectedto produce a baseline signal Mb which is fed to computer 218 via line217. A wool fibre in the isopropanol-wool slurry is passed through theinteraction volume to partially occlude the collimated validating andmeasurement beam, thereby producing a validating and measurementoutgoing light beam. A portion of the outgoing light is reflected bypartial mirror 221 back through cell 220 where it again interacts withthe wool fibre to form the measurement outgoing light beam. A portion ofthe measurement outgoing light beam is injected into the core of fibre207 at end 208 a portion of which is guided to diode 216 via fibre 207,ports 205 and 206 of coupler 209 and fibre 215 where it is detected toproduce a measurement signal Mm which is fed to computer 218 via line217. Because of the geometry of the core at end 208 of fibre 207, lens219 and partial mirror 221, validating and measurement light source 201is effectively at infinity and measurement photodiode 216 is effectivelyat infinity. Therefore, measurement signal Mm is substantiallyindependent of wool fibre diameter independent parameters, such as axialposition along the collimated validating and measurement beam, fibremedcuation and fibre colour, and when a single wool fibre completelycrosses the collimated validating and measurement beam in theinteraction volume and is centred in the collimated validating andmeasurement beam, the signal Mm will depend almost solely on thediameter of the fibre. (Note that there are some minor orientationeffects due to the polarisation of the collimated validating andmeasurement beam.) When Mm passes through a minimum, computer 218interrupts its current task, stores the minimum Mmm, the minimum time atwhich the minimum occurred and the last baseline signal Mb in temporarymemory.

The optical power of the laser light injected into the core of fibre 202by laser 201 is maintained at a constant level by feedback control asfollows. A predetermined amount of the light injected into the core offibre 202 by laser 201 is guided to photodiode 211, via fibre 202, ports203 and 204 of coupler 209 and fibre 210, which detects the light leveland produces a light level signal which is proportional to the lightlevel detected by diode 211. The light level signal is passed to supply213 via line 212. Supply 213 adjusts the current fed to diode 201 vialine 214 to keep the light level signal constant at some predeterminedvalue.

The portion of the validating and measurement outgoing light beam thatpasses through partial minor 221 as validating outgoing light isfocussed by lens 222 to form a highly visible diffraction pattern at end223 of bundle 224. A portion of the highly visible diffraction patternenters the cores of the fibres in bundle 224 at end 223 to be guided toand detected by validating detector and neural network 225. Validatingdetector and neural network 225 has previously been `taught` torecognise the time at which a single wool fibre completely crosses thecollimated validating and measurement beam in the interaction volume andis centred in the collimated validating and measurement beam. Whenvalidating detector and neural network 225 encounters such a signal, itpasses a true validation signal to computer 218 via line 226 togetherwith the validation true time at which the validation detector andneural network received the corresponding validation outgoing light viabundle 224. Computer 218 then interrupts its current task and stores thevalidation true time and increments a valid fibre counter.

When it is not busy storing measurement and validation signals, computer218 matches each validation true time with the corresponding minimumtime, calculates the occlusion percentage Oc from the correspondingminimum Mmm and baseline signal Mb using the formula Oc=100 (1-Mmm/Mb).The fibre diameter is then determined from the occlusion percentageusing a calibration curve, the obtaining of which will be describedbelow, and stores the fibre diameter in permanent memory. Minimum,baseline signals and minimum times that don't correspond closely withvalidation true times are discarded. Validation true times that don'tcorrespond closely with minimum times are discarded and for eachvalidation true time discard, the valid fibre counter is decremented.

The above process is repeated until the valid fibre counter reaches apredetermined amount, typically 1,000 to 10,000, at which time computer218 matches the remaining minimum times and validation true times anddetermines and stores the corresponding fibre diameters in permanentmemory. Once all of the fibre diameters have been stored in permanentmemory, computer 218 determines from the permanently stored wool fibrediameters the mean and standard deviation.

The calibration curve is obtained as follows. A calibration sample witha range of typically wire fibres having known diameters typically in therange of 5 micrometers to 200 micrometers is placed on sample carrier229. Computer 218 then directs mechanical stage 228, via line 227, topass the calibration sample through the collimated validating andmeasurement beam. The minimum Mmm resulting from the passage of eachfibre in the calibration sample through the collimated validating andmeasurement beam, together with the baseline signal Mb accepted bycomputer 218 between each accepted Mmm signal, is stored by computer 218and each minimum Mmm is matched with the corresponding known diameter.This process is repeated a number of times, typically in excess of 10times, and the average occlusion percentage Oc determined for eachcalibration fibre. A calibration curve is then fitted to the occlusionpercentages and known diameters and the calibration curve is stored bycomputer 218.

In an alternative mode of operation apparatus 200 determines the meanand standard deviation as follows. A sample comprising wool fibres ofunknown diameter are placed on sample carrier 229 and passed through thecollimated validating and measurement beam and the mean and standarddeviation of the diameters of the fibres in the sample determined asdescribed above. In this instance, the validating and measurementinteraction volume is defined by the intersection of the sample on thesample carrier and the collimated validating and measurement beam whenthe sample is passed through the beam. Since the highly visiblediffraction pattern produced by the wool fibres and lens 222 on end 223of bundle 224 will be different to that described above, the algorithmused by validating detector and neural network 225 will also bedifferent.

INDUSTRIAL APPLICABILITY

The methods and apparatus of the invention may be utilised to determinea first parameter(s) of a valid object, such as shape, diameter, area,chemical composition, colour, number of parts, thickness, width, length,absorptivity, reflectivity, transmittivity, dielectric constant, Ramanscattering profile, fluorescence, surface texture or other surfacedetail, position, orientation, surface tension, surface roughness,surface profile or density, for example. In the case of a fibrous objectfor example the first parameter may be diameter, for example. Themeasurements may be readily performed on a plurality of objects andstatistical information readily determined from the measurements.

We claim:
 1. A method for determining a measurement parameter of afibrous object and whether the object is a valid object, comprising:(a)passing a validating energy beam through a validating interactionvolume; (b) detecting validating outgoing energy originating from thevalidating energy beam in the validating interaction volume, thedetection being in at least one validating focal plane of the validatingoutgoing energy with respect to the validating interaction volume anddetermining a validating parameter from the detected validating outgoingenergy wherein the validating parameter is indicative of whether anobject in the validating interaction volume is a single object in avalid measuring position and orientation; (c) determining from thevalidating parameter whether the validating outgoing energy originatedfrom an interaction between a fibrous object and validating beam in thevalidating volume and, on determining an object; (d) passing ameasurement energy beam through the measurement interaction volume, saidmeasurement interaction volume being the same as the validatinginteraction volume, to interact with the object whereby at least a partof the measurement energy beam is occluded by the fibrous object so asto produce measurement outgoing energy in the form of a diffractionpattern; (e) detecting a portion of the measurement outgoing energy inat least one measurement focal plane of the measurement outgoing energywith respect to the measurement interaction volume, the measurementfocal plane being different from the validating focal plane, and whereinthe detected portion of said measurement outgoing energy is not so muchthat parameters independent of the measurement parameter preventdetermination of the measurement parameter from the measurement outgoingenergy to a required accuracy and determining a measurement parameter tothe required accuracy from the detected measurement outgoing energy; and(f) determining from the validating parameter whether the fibrous objectis a valid object, said object being a valid object when it is a singleobject in a valid measuring position and orientation; and, ondetermining a valid object, determining a first parameter of the validfibrous object from the measurement parameter and determining the firstparameter of the valid fibrous object as an acceptable valid objectparameter wherein the first parameter is a diameter of the fibrousobject.
 2. A method for determining a measurement parameter of a validobject, comprising:the method of claim 1; and, on determining a validobject, determining the measurement parameter of the valid object as anacceptable valid object parameter.
 3. A method for determining ameasurement parameter of an invalid object, comprising:the method ofclaim 1; and, on determining an invalid object, determining themeasurement parameter of the invalid object as an unacceptable validobject parameter.
 4. The method of claim 1 whereinthe validating energybeam is the same as the measurement energy beam and is a collimatedlight beam; the validation interaction volume is the same as themeasurement interaction volume and is one interaction volume; thevalidating parameter is the intensity from at least part of an image ofthe interaction volume produced using the validating outgoing energy,the validating outgoing energy being in the form of light; and themeasurement parameter is the intensity of at least a portion of themeasurement outgoing energy said measurement outgoing energy being adiffraction pattern.
 5. The method of claim 1 whereina valid fibrousobject comprises a fibre selected from a group including fibreglassfibre, hessian fibre, nylon fibre, glass fibre, polnosic fibre,polyester fibre, abaca fibre, silk fibre, jute fibre, flax fibre,cellulose fibre, regenerated fibre, sisal fibre, carbon fibre, stainlesssteel fibre, vegetable fibre, polyolefin fibre, steel fibre, boronfibre, copper fibre, brass fibre, teflon fibre, dacron fibre, mylarfibre, aluminium fibre, aluminium alloy fibre, polyamide fibre,polyacrylic fibre, nylon 66 polyacrylonitrile fibre, polyvinyl alcoholfibre, edible vegetable fibre, inedible vegetable fibre, wood pulpfibre, cotton fibre, animal fibre, meat fibre, sheep wool fibre, hair,human hair, goat hair, cattle hair, yarn, wool yarn, cotton yarn,string, wire and optical fibre; and has a preselected length in apreselected position and orientation in the validation and measurementinteraction volume.
 6. The method of claim 1 whereinthe validatingenergy beam is the same as the measurement energy beam and is anexpanding beam of light emerging from a pinhole illuminated by acollimated light beam; the validation interaction volume is the same asthe measurement interaction volume and is one interaction volume; thevalidating parameter is the intensity from at least part of an image ofthe interaction volume produced using the validating outgoing energy,the validating outgoing energy being in the form of light; themeasurement parameter is the intensity of at least a portion of themeasurement outgoing energy said measurement outgoing energy being adiffraction pattern; a valid object comprises a fibre selected from thegroup consisting of a sheep wool fibre and goat hair; and has apreselected length in a preselected position and orientation in thevalidation and measurement interaction volume and the first parameter isthe diameter of the fibre; and the method further comprises repeatingthe method of claim 1 a plurality of times and determining statisticalinformation in respect of a plurality of the diameters of this validobject.
 7. The method of claim 1 whereinthe validating energy beam isthe same as the measurement energy beam and is a collimated light beam;the validation interaction volume is the same as the measurementinteraction and is one interaction volume; the validating parameter isthe intensity from at least part of an image of the interaction volumeproduced using the validating outgoing energy, the validating outgoingenergy being in the form of light; the measurement parameter is theintensity of at least a portion of the measurement outgoing energy saidmeasurement outgoing energy being a diffraction pattern; a valid objectcomprises a fibre selected from the group consisting of a sheep woolfibre and goat hair; and has a preselected length in a preselectedposition and orientation in the validation and measurement interactionvolume and the first parameter is the diameter of the fibre; and themethod further comprises repeating the method of claim 1 a plurality oftimes and determining statistical information in respect of a pluralityof the diameters of the valid object.
 8. A method for determining adiameter of a fibrous object and determining a first parameter of aninvalid object, comprising:passing a validating energy beam through avalidating interaction volume; detecting validating outgoing energyoriginating from the validating energy beam in the validatinginteraction volume, the detection being in at least one validating focalplane of the validating outgoing energy with respect to the validatinginteraction volume and determining a validating parameter from thedetected validating outgoing energy; determining from the validatingparameter whether the validating outgoing energy originated from aninteraction between said fibrous object and the validating beam in thevalidating volume and, on determining said fibrous object; locating saidfibrous object in a measurement interaction volume; passing ameasurement energy beam through the measurement interaction volume tointeract with said fibrous object so as to produce measurement outgoingenergy; detecting at least a portion of the measurement outgoing energyin at least one measurement focal plane of the measurement outgoingenergy with respect to the measurement interaction volume, themeasurement focal plane being different from the validating focal plane,and determining a measurement parameter from the detected measurementoutgoing energy; and determining from the validating parameter whetherthe fibrous object is a valid object; determining the diameter of thefibrous object from the measurement parameter; and, on determining aninvalid object, determining the first parameter of the invalid object asan unacceptable valid object parameter.
 9. A method for determining ameasurement parameter of a valid object and determining a measurementparameter of an invalid object, comprising:passing a validating energybeam through a validating interaction volume; detecting validatingoutgoing energy originating from the validating energy beam in thevalidating interaction volume, the detection being in at least onevalidating focal plane of the validating outgoing energy with respect tothe validating interaction volume and determining a validating parameterfrom the detected validating outgoing energy; determining from thevalidating parameter whether the validating outgoing energy originatedfrom an interaction between a fibrous object and the validating beam inthe validating volume and, on determining an object; locating thefibrous object in a measurement interaction volume; passing ameasurement energy beam through the measurement interaction volume tointeract with the fibrous object so as to produce measurement outgoingenergy; detecting at least a portion of the measurement outgoing energyin at least one measurement focal plane of the measurement outgoingenergy with respect to the measurement interaction volume, themeasurement focal plane being different from the validating focal plane,and determining a measurement parameter from the detected measurementoutgoing energy; and determining from the validating parameter whetherthe fibrous object is a valid object; and, (I) on determining a validobject,determining the measurement parameter of the valid object as anacceptable valid object parameter, wherein said measurement parameter isa diameter of the fibrous object; (II) on determining an invalidobject,determining the measurement parameter of the invalid object as anunacceptable valid object parameter.
 10. A method for determining adiameter of a fibrous object and determining a measurement parameter ofan invalid object, comprising:passing a validating energy beam through avalidating interaction volume; detecting validating outgoing energyoriginating from the validating energy beam in the validatinginteraction volume, the detection being in at least one validating focalplane of the validating outgoing energy with respect to the validatinginteraction volume and determining a validating parameter from thedetected validating outgoing energy; determining from the validatingparameter whether the validating outgoing energy originated from aninteraction between the fibrous object and the validating beam in thevalidating volume and, on determining the fibrous object; locating thefibrous object in a measurement interaction volume; passing ameasurement energy beam through the measurement interaction volume tointeract with the fibrous object so as to produce measurement outgoingenergy; detecting at least a portion of the measurement outgoing energyin at least one measurement focal plane of the measurement outgoingenergy with respect to the measurement interaction volume, themeasurement focal plane being different from the validating focal plane,and determining a measurement parameter from the detected measurementoutgoing energy; and determining from the validating parameter whetherthe fibrous object is a valid object; and, (I) on determining a validobject,determining the diameter of the fibrous object from themeasurement parameter; determining the diameter of the valid object asan acceptable valid object parameter; (II) on determining an invalidobject,determining the measurement parameter of the invalid object as anunacceptable valid object parameter.
 11. The method of any one of claims1 or 3 to 7 whereinthe validating energy beam is the same as themeasurement energy beam and is an expanding beam of light emerging froma pinhole illuminated by a collimated light beam; the validationinteraction volume is the same as the measurement interaction volume andis one interaction volume; the validating parameter is the intensityfrom at least part of an image of the interaction volume produced usingthe validating outgoing energy, the validating outgoing energy being inthe form of light; and the measurement parameter is the intensity of atleast a portion of the measurement outgoing energy said measurementoutgoing energy being a diffraction pattern.
 12. An apparatus fordetermining a measurement parameter of a fibrous object and whether theobject is a valid object, comprising:(a) a validating energy source forpassing a validating energy beam through a validating interactionvolume; (b) a validating detector for detecting validating outgoingenergy originating from the validating energy beam in the validatinginteraction volume, the detection being in at least one validating focalplane of the validating outgoing energy with respect to the validatinginteraction volume and means for determining a validating parameter fromthe detected validating outgoing energy operatively associated with thevalidating detector, the validating parameter being a diameter of thefibrous object, the validating detector being operatively associatedwith the validating energy source wherein the validating parameter isindicative of whether the fibrous object in the validating interactionvolume is a single object in a valid measuring position and orientation;(c) verification means for determining from the validating parameterwhether the validating outgoing energy originated from an interactionbetween the fibrous object and the validating beam in the validatingvolume, the verification means being operatively associated with thevalidating detector; (d) a measurement energy source for passing ameasurement energy beam through a measurement interaction volume, saidmeasurement interaction volume being the same as the validatinginteraction volume, to interact with the fibrous object whereby at leasta part of the measurement energy beam is occluded by the fibrous objectso as to produce measurement outgoing energy in the form of adiffraction pattern; (e) a measurement detector for detecting a portionof the measurement outgoing energy in at least one measurement focalplane of the measurement outgoing energy with respect to the measurementinteraction volume, the measurement focal plane being different from thevalidating focal plane, and wherein the detected portion of saidmeasurement outgoing energy is not so much that parameters independentof the measurement parameter prevent determination of the measurementparameter from the measurement outgoing energy to a required accuracyand means for determining a measurement parameter from the detectedmeasurement outgoing energy operatively associated with the measurementdetector, the measurement detector being operatively associated with themeasurement energy source; and (f) means for determining from thevalidating parameter whether the fibrous object is a valid object, themeans for determining being operatively associated with the validatingdetector, the fibrous object being a valid object when it is a singleobject in a valid measuring position and orientation.
 13. An apparatusas in claim 12 which includes:means for determining the first parameterof the object from the measurement parameter, operatively associatedwith the measurement detector.
 14. An apparatus as in claim 12 whichincludes:means for determining the first parameter of the valid objectfrom the measurement parameter and for determining the first parameterof the valid object as an acceptable valid object parameter, operativelyassociated with the measurement detector and the means for determiningfrom the validating parameter whether the object is a valid object. 15.An apparatus as in claim 12 which includes:means for determining themeasurement parameter of the valid object as an acceptable valid objectparameter, operatively associated with the measurement detector and themeans for determining from the validating parameter whether the objectis a valid object.
 16. An apparatus as in claim 12 which includes:meansfor determining the measurement parameter of the invalid object as anunacceptable valid object parameter, operatively associated with themeasurement detector and the means for determining from the validatingparameter whether the object is a valid object.
 17. An apparatus as inclaim 12 which includes:means for determining the first parameter of theobject from the measurement parameter and for determining the firstparameter of the invalid object as an unacceptable valid objectparameter, operatively associated with the measurement detector and themeans for determining from the validating parameter whether the objectis a valid object.
 18. An apparatus as in claim 12 which includes:meansfor determining the measurement parameter of the valid object as anacceptable valid object parameter and for determining the measurementparameter of the invalid object as an unacceptable valid objectparameter, operatively associated with the measurement detector and themeans for determining from the validating parameter whether the objectis a valid object.
 19. An apparatus as in claim 12 which includes:meansfor determining the first parameter of the object from the measurementparameter and for determining the first parameter of the valid object asan acceptable valid object parameter and for determining the measurementparameter of the invalid object as an unacceptable valid objectparameter, operatively associated with the measurement detector and themeans for determining from the validating parameter whether the objectis a valid object.
 20. The apparatus of claim 12 whereinthe validatingenergy source is the same as the measurement energy source; thevalidating energy beam is the same as the measurement energy beam and isan expanding beam of light emerging from a pinhole illuminated by acollimated light beam; the validation interaction volume is the same asthe measurement interaction volume and is one interaction volume; andthe validating parameter is the intensity from at least part of an imageof the interaction volume produced using the validating outgoing energy,the validating outgoing energy being the form of light; and themeasurement parameter is the intensity of at least a portion of themeasurement outgoing energy said measurement outgoing energy being adiffraction pattern.
 21. The apparatus of claim 12 whereinthe validatingenergy source is the same as the measurement energy source; thevalidating energy beam is the same as the measurement energy beam and isa collimated light beam; the validation interaction volume is the sameas the measurement interaction volume and is one interaction volume; thevalidating parameter is the intensity from at least part of an image ofthe interaction volume produced using the validating outgoing energy,the validating outgoing energy being in the form of light; and themeasurement parameter is the intensity of at least a portion of themeasurement outgoing energy said measurement outgoing energy being adiffraction pattern.
 22. The apparatus of claim 12 whereina valid objectcomprises a fibre selected from a group including fibreglass fibre,hessian fibre, nylon fibre, glass fibre, polnosic fibre, polyesterfibre, abaca fibre, silk fibre, jute fibre, flax fibre, cellulose fibre,regenerated fibre, sisal fibre, carbon fibre, stainless steel fibre,vegetable fibre, polyolefin fibre, steel fibre, boron fibre, copperfibre, brass fibre, teflon fibre, dacron fibre, mylar fibre, aluminumfibre, aluminium alloy fibre, polyamide fibre, polyacrylic fibre, nylon66 polyacrylonitrile fibre, polyvinyl alcohol fibre, edible vegetablefibre, inedible vegetable fibre, wood pulp fibre, cotton fibre, animalfibre, meat fibre, sheep wool fibre, hair, human hair, goat hair, cattlehair, yarn, wool yarn, cotton yarn, string, wire and optical fibre; andhas a preselected length in a preselected position and orientation inthe validation and measurement interaction volume.
 23. The apparatus ofclaim 12 whereinthe validating energy source is the same as themeasurement energy source; the validating energy beam is the same as themeasurement energy beam and is an expanding beam of light emerging froma pinhole illuminated by a collimated light beam; the validationinteraction volume is the same as the measurement interaction volume andis one interaction volume; the validating parameter is the intensityfrom at least part of an image of the interaction volume produced usingthe validating outgoing energy, the validating outgoing energy being inthe form of light; the measurement parameter is the intensity of atleast a portion of the measurement outgoing energy said measurementoutgoing energy being a diffraction pattern; a valid object comprises afibre selected from a group including sheep wool fibre and goat hair;and has a preselected length in a preselected position and orientationin the validation and measurement interaction volume and the firstparameter is the diameter of the fibre; and the apparatus furthercomprises means for determining statistical information in respect of aplurality of the diameters of the valid object.
 24. The apparatus ofclaim 12 whereinthe validating energy source is the same as themeasurement energy source; the validating energy beam is the same as themeasurement energy beam and is a collimated light beam; the validationinteraction volume is the same as the measurement interaction volume andis one interaction volume; the validating parameter is the intensityfrom at least part of an image of the interaction volume produced usingthe validating outgoing energy, the validating outgoing energy being inthe form of light; the measurement parameter is the intensity of atleast a portion of the measurement outgoing energy said measurementoutgoing energy being a diffraction pattern; a valid object comprises afibre selected from the group consisting of a sheep wool fibre and goathair; and has a preselected length in a preselected position andorientation in the validation and measurement interaction volume and thefirst parameter is the diameter of the fibre; and the apparatus furthercomprises means for determining statistical information in respect of aplurality of the diameters of the valid object.
 25. The apparatus ofclaim 12 whereinthe validating outgoing energy is light; and furthercomprising a light focuser to form an image of the validatinginteraction volume on the validating detector, operatively associatedwith the validating source and validating detector.
 26. The apparatus ofclaim 12 whereinthe measurement outgoing energy is light; and furthercomprising a light focuser to form an image of the measurementinteraction volume on the measurement detector, operatively associatedwith the measurement source and measurement detector.
 27. The apparatusof claim 12 further comprisingmeans to pass an object through themeasurement and validating interaction volumes, operatively associatedwith the validating energy source, measurement energy source and themeans for locating.
 28. The apparatus of any one of claims 13, 14, 17and 19 further comprisingmeans for storing and retrieving themeasurement parameter(s) and the object validation and for storing thefirst parameter(s), operatively associated with the measurementdetector(s) and the means for determining the first parameter(s) and themeans for determining from the validating parameter(s) whether theobject is a valid object.
 29. The apparatus of any one of claims 12 to19 whereinthe validating detector comprises an array of detectingelements.
 30. The apparatus of any one of claims 12 to 19 whereinthemeasurement detector comprises an array of detecting elements.
 31. Theapparatus of any one of claims 12 to 19 whereinthe validating outgoingenergy is light; and the validating detector comprises an optical fibrecoupled to a detecting element.
 32. The apparatus of any one of claims12 to 19 whereinthe measurement outgoing energy is light; and themeasurement detector comprises an optical fibre coupled to a detectingelement.
 33. An apparatus for determining at least one characteristic ofa fibrous object comprising:a source for generating a beam of radiantenergy; an object receiving sample volume wherein at least a portion ofsaid beam is incident thereon and a portion of which passes therethroughand exits therefrom; a validating detector positioned at a first focalplane with respect to a beam portion exiting said volume and responsiveto radiant energy incident thereon; circuitry coupled to said detector,for determining a validating parameter, said validating parameter beinga diameter of the fibrous object; verification circuitry, coupled tosaid determining circuitry, responsive to said validating parameter fordetermining a source characteristic of said incident radiation; ameasurement detector, positioned at a second focal plane with respect toa beam portion exiting said volume and responsive to radiant energyincident thereon; circuitry coupled to said measurement detector fordetermining a measurement parameter; processing circuitry, coupled tosaid measurement parameter determining circuitry and to said validatingparameter determining circuitry, for determining if the object exhibitsthe characteristic.